The use of vinyl acetate containing aqueous copolymers as binders for bonding and coating different substrates is known. A wide range of comonomers such as for example ethylene or vinyl esters of α-substituted fatty acids are often used to improve hydrophobicity and hydrolytic stability of the vinyl acetate copolymers.
JP 2004-217724 discloses an aqueous emulsion which has good water resistance, polymerisation stability and storage stability and a process to prepare the emulsion polymer. The vinyl ester monomer that can be used is vinyl acetate with the addition of ethylene. The emulsion can be used as an adhesive for paper coatings, general woodwork, and as a binder for nonwoven products.
US 2002/0065361 discloses a polyvinyl ester resin emulsion having a high viscosity and good water resistance. The emulsion is produced in a method of polymerizing a vinyl ester monomer in the presence of polyvinyl alcohol serving as protective colloid and in the presence of a water-insoluble, hydroxyl-group containing compound, and can be used as an adhesive that can be readily formed into transparent films. Vinyl esters that can be used include vinyl formate, vinyl acetate, vinyl propionate and vinyl pivalate. Ethylene can be added to the emulsion in the range of 3-35% by weight to improve the water resistance and heat resistance.
US 2002/069965 discloses a process for preparing adhesives wherein the adhesive has improved adhesion. The adhesive is made by polymerizing a comonomer mixture comprising the following of: a) one or more monomers from the group consisting of the vinyl esters of unbranched and branched carboxylic acids of 1 to 10 carbon atoms, the esters of acrylic acid and methacrylic acid with branched and unbranched alcohols of 1 to 12 carbon atoms, vinyl aromatic compounds, vinyl halides and α-olefins, and b) from 0.01 to 50% by weight, based on the overall weight of the comonomers, of a vinyl ester of α-branched tertiary monocarboxylic acids of 11 carbon atoms, in the presence of c) from 0.1 to 15% by weight, based on the overall weight of the comonomers, of polyvinyl alcohol. Some of the preferred vinyl esters can be vinyl acetate, VeoVa 9/10 and vinyl 2-ethylhexanoate.
EP 0851015 discloses an adhesive having low VOC that is based on a polyvinyl alcohol stabilized vinyl ester ethylene copolymer dispersion comprising of 100 parts by weight polyvinyl ester portion, 10 to 100 parts by weight vinyl ester ethylene copolymer, and 1 to 10 parts by weight part or full-soaped polyvinyl alcohol with a viscosity from 40 to 120 mPas and a degree of hydrolysis from 85 to 100 mol %. The polyvinyl ester portion contains 80-100% by weight of several vinyl esters of branched or unbranched alkyl carboxylic acids with 1-18 carbon atoms and 0-20% by weight other or multiple ethylenic unsaturated monomer units.
EP 1580244 discloses a water-based bicomponent wood adhesive having improved heat resistance and extended pot life. The adhesive is comprised of vinyl acetate and N-methylolacrylamide as a crosslinking-agent and also including an aromatic and/or cyclo aliphatic monomer, such as 2-phenoxy ethyl acrylate and/or isobornyl methacrylate, and methyl methacrylate. Additional vinyl esters that can be used are vinyl formate, vinyl isobutyrate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl esters of saturated, branched monocarboxylic acids having 9 to 10 carbon atoms in the acid radical, such as VeoVa9 or VeoVa10, vinyl esters of relatively long-chain, saturated or unsaturated fatty acids, such as, for example, vinyl laurate, vinyl stearate and vinyl esters of benzoic acid and substituted derivatives of benzoic acid, such as vinyl p-tertbutylbenzoate.
U.S. Pat. No. 5,434,216 discloses a latex adhesive used for woodworking having improved water, heat and creep resistance. The composition of the adhesive is based on vinyl acetate/N-methylolacrylamide polymer emulsions which are stabilized with 1.5 to 2.5% by weight of 88% hydrolyzed polyvinyl alcohol and 1 to 4% by weight of 95-99.5% hydrolyzed polyvinyl alcohol, the two alcohols comprising at least 3% by weight of the emulsion solids. The N-methylolacrylamide and vinyl acetate copolymers can also be used in combination with: (1) other vinylesters including vinyl formate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl valerate, vinyl 2-ethyl hexanoate, vinyl isooctanoate, vinyl nonanoate, vinyl decanoate, vinyl pivalate or vinyl versatate; (2) ethylene; (3) alkyl esters of acrylic and methacrylic acid such as methyl acrylate, methyl methacrylate, ethyl acrylate or ethyl methacrylate; (4) substituted or unsubstituted mono and dialkylesters of α,β-unsaturated dicarboxylic acids such as the substituted and unsubstituted mono and dibutyl, mono and diethyl maleate esters as well as the corresponding fumarates, itaconates and citronates; (5) α,β-unsaturated carboxylic acids such as crotonic, acrylic, methacrylic, fumaric, maleic, itaconic and citraconic acids.
US 2010/0167610 discloses a polymer composition suitable as a binder resin for fibrous substrates such as woven or nonwoven products including textiles, apparel in general, papers, scrim, engineered fabrics, glass or other mineral fibers, roofing or flooring materials. The binder resin comprises a copolymer obtained by reacting (i) vinyl acetate, (ii) at least one vinyl ester of α-monosubstituted fatty acids; and (iii) at least one functional monomer, such as self-crosslinking monomer, and optionally other comonomers. In particular vinyl 2-ethylhexanoate is used as α-monosubstituted fatty acid.
US 2010/0167609 discloses a polymer composition comprising a copolymer obtained by reacting vinyl acetate; at least one vinyl ester of neoalkanoic acids and at least one additional component selected from the group consisting: (i) at least one α-olefin; (ii) at least one functional monomer; (iii) at least one ester of ethylenically unsaturated carboxylic acids. The compositions are especially useful in or as binders for fibrous substrates, such as woven or nonwoven products including textiles, apparel in general, papers, scrim, engineering fabrics, glass or mineral fibers, roofing or flooring material.
FR 1 525 842 A discloses a copolymer composition comprising a vinyl ester with a linear alkyl chain, such as vinyl acetate, a vinyl ester of a tertiary alkanoic acid and an ester of methacrylic acid. The copolymer composition is used in paints.
Copolymers of vinyl acetate and vinyl esters of neoalkanoic acid have been discussed in the literature for use in paints. New Vinyl Ester Monomers for Emulsion Polymers, Progress in Organic Coating, Vol. 22, pp. 19-25, Elsevier (1993) discusses water resistance and coating performance and Hydrophobic Coatings from Emulsion Polymers, Journal of Coating Technology, Vol. 73, No. 912, pp. 43-55 (2001) discusses pigmented paints.
U.S. Pat. No. 5,576,384 discloses low-emission dispersion paints with a copolymer composition comprising monomer units derived from unsaturated hydrolysable organic silicon compounds and which are based on vinyl esters, such as vinyl acetate and vinyl versatate.
U.S. Pat. No. 2,600,450 A refers to a copolymer composition comprising an ester of acrylic acid and a vinyl ester, such as vinyl 2-ethylhexanoate or vinyl 3,5,5-trimethylhexanoate. The copolymers are used as pour point depressants for wax-containing hydrocarbon liquids.
Thus, the art refers to the use of vinyl versatate as a comonomer in such copolymers. Versatic acids, in particular C9-C11 acids, are prepared by reacting of olefinically compounds with carbon monoxide and then with water to produce highly branched acids containing a neo structure on the α-carbon atom adjacent to the carboxyl group. Said neoalkanoic acids are commercially available under the tradename Versatics, VeoVa 9 or VeoVa 10, from Shell. The preparation process is conducted in a technical manner in the presence of Lewis acids, such as boron trifluoride, as disclosed in Weissermel, Arpe, Industrielle Organische Chemie, 3rd Edition, 1988, pg. 150-152. Due to the neighboring group steric effect, esters based on versatic acids exhibit a high heat resistance and high hydrolytic stability towards water and vinyl esters of C9-C11 versatic acids (VeoVa10) are used in the manufacture of copolymers for binders in resins. An example of such copolymer comprises 30% VeoVa10 and 70% vinyl acetate, as disclosed in New Vinyl Ester Monomers for Emulsion Polymer, Progress in Organic Coatings, Vol. 22, pg. 19-25, Elsevier (1993).
The manufacturing process of versatic acids requires the addition of carbon monoxide to the oligomeric olefin under pressure in the presence of a Lewis acid and then in a second step, the addition of water to recover the desired acid. Due to the complex manufacturing process versatic acids are quite costly and available to a limited amount.